Logo
FULL SITE MENU

Powerpack woes

S

scottalan

New member
" i rebuilt a 1975 75hp johnso

" i rebuilt a 1975 75hp johnson...i was told the powerpack was kaputt...i replaced the power pack with a new one...i only have the engine..the boat is elsewhere...i crank it (via a battery jumpered to the starter) but i get no spark...the sensors are putting out 3 VAC(cranking)..the charge coils put out 170VAC (i do not have a peak voltmeter, just a good digital)...i have looked at the diagram from my climers repair book an see that the sensor coils are tied into the powerpack different in 1974/5 than they were in 1976/7...i see they are attached in the 1976/7 way...

my questions are: 1) shouldn't the motor still produce a spark output even if the electrical connections to the boat are not attached...according to the wiring diagram it appears the key just grounds out the powerpack to shut off the motor...

did OMC make different powerpacks for the 74/5 and the 76/7 model years?...the guy i bought mine from just gave me what i thought was the correct one... "
 
"Scott... At cranking speed, t

"Scott... At cranking speed, to check the spark (should jump a 7/16" gap), the spark plugs must be removed. The engine must turn over at approximately 300 rpm in order to produce that spark on all four cylinders.

The sensors tie into terminals 9 & 12...and 2 & 4 on the pack regardless of the year. I"m curious as to what you mean when you say they're different. The pack terminals are marked as:

7-8-9-10-11-12
1-2-3--4--5--6

Joe
"
 
" as i found it (the power

" as i found it (the powerpack)...the terminals are tied to the following
1-coil one
2-coil two
3-coil three
4 and 5 -charge coil
6 -ignition switch
7 -open
8 -sensor one
9 -sensor two
10 -sensor three
11- common wire to all sensors
12 -engine ground

in one wiring diagram i find that the common wire to the sensors is on the number eight position, and the sensors are all shifted down one...
the replacement powerpack was different in material (plastic) and had no numbering...the one end had three holes and the other one hole (for mounting to the engine) the cover was square, the original was square but with a different style bolt pattern(three screws not four like the new one)...very confusing...if you don't know which way is up(as they don't mark the powerpacks)..and if there are no numbers..and if the clymers has two different schematics for how the coils an sensors are attached to the powerpack(depending on if the year is 1974/5 or 1976/7...the whole mess just is plain stupid and confusing....again...i am not a spring chicken...had a bunch of electronics in the canoe club (U.S navy)...i think i am confortable with how the boxes work...but they don't help us much if they don't number the darn electrical contacts do they?..cranking it i get proper voltages at the charge coils and sensor coils...just no output...powerpack is not grounded at the number six electrical contact so it should be firing...
I am surprised, well not really, that bombadier has no way to really contact them for technical support...at least via the net...

did i give you enough information?....
'ppreciate the help...very frustrating...
thanks scott... "
 
"Scott....As one non-spring ch

"Scott....As one non-spring chicken to another <grin>, I know where you're coming from. I should have listed that pack as:
1 7
2 8
3 9
4 10
5 11
6 12
I'm looking at my 1976 wiring diagram and it lists the pack as being wired exactly as you state above. Note that the #4 charge coil wire must be the "Brown" wire, and #5 must be the "Brown/Orange" wire. If they're reversed, you will have no ignition (spark). Also #12 which is the pack ground going from the pack to (usually) the p/pack retaining bolt. That bolt is (usually)simply screwed into a bracket so make sure that the bracket is securely grounded. Note that the old stle metal powerpacks were superceeded by the plastic models and are more dependable. The three (3) cylinder models from 1973 to 1978 all use the same p/pack as explained below.

The p/packs are designed so that they will fit into the bracket only one way (at least, that's how I remember it). Number one (1) terminal would be at the top left. On the back of the pack, the triangle shaped part is up.

In searching back through my books and bulletins, this is what I've found. The original metal powerpacks were installed on the 1973,74,and 1975 65hp, 70hp,and 75hp models with the OMC part number of 384997 in 1973, and 581334 starting in 1974. Both of these numbers superceeded up to #581726 which is the plastic type pack "WITHOUT" the cover plate. In 1976, the 70hp and 75hp had the plastic type packs installed with the #581551 which superceeded up to #581493, and then to #582057 which is the same pack as the #581726 but it is equipped "WITH" the cover plate. The 1977 70hp/75hp came with pack #581713 which superceeded to #582057. The 1978 70hp/75hp came with #581725 which also superceeded to #582057.

Bottom line is that there is only one p/pack for the three (3) cylinder engines that use the terminal type pack. The part number varies due to being with or without a cover plate.

581726 = No Cover Plate
582057 = With cover plate.

Note that any of the older packs mentioned above under their various part numbers will work also.

I can find no mention of differing wiring diagrams such as you mention about the common sensor wire being shifted down etc. If you could get that info to me via an attachment to a e-mail or any other way, I'd appreciate seeing it.

Joe
"
 
" Scott, and everyone else rea

" Scott, and everyone else reading this.... Pertaining to my previous post of 08/27/01 where I make mention of the sensor wires and terminals 9-12 and 2-4, please disregard it. It was in error due to myself being involved in too many projects at one time. The correct posting is above, dated 08/28/01. Thanks.

Joe "
 
Re: "Scott....As one non-spring ch

Hey Guys! Stupid Question here. What are power Packs? I own a 1976 75hp Johnson & probably should know. I haven't yet recieved my manuals...
 
The powerpack is that little box that takes the place of points / distributor like found in older engines.----Basically stores a charge from the stator in a capacitor and the " silicon contolled rectifiers " in them release that charge to the coils.-----The " scr 's " get a signal from the sensor coils found in the timer base.----Really it is simple stuff and extremely easy to trouble shoot when you understand how it all works.
 
You must log in or register to reply here.
Back
Top